FILE- In this Dec. 8, 2005, file photo, a man walks out the Verizon's new corporate headquarters(AP Photo/Dima Gavrysh, File)AP2005

The National Security Agency has been collecting phone records of millions of U.S. Verizon customers under a top-secret court order, according to published reports.

The Obama administration on Thursday defended the practice.

The order was granted by the secret Foreign Intelligence Surveillance Court on April 25 and is good until July 19, Britain's The Guardian newspaper reported Wednesday. The order requires Verizon, one of the nation's largest telecommunications companies, on an "ongoing, daily basis" to give the NSA information on all telephone calls in its systems, both within the U.S. and between the U.S. and other countries.

The Obama administration defended the National Security Agency's need to collect telephone records of U.S. citizens, calling such information "a critical tool in protecting the nation from terrorist threats."

While defending the practice, a senior administration official did not confirm a newspaper report that the NSA has been collecting the telephone records of millions of U.S. customers of Verizon under a top secret court order.

The newspaper said the document, a copy of which it had obtained, shows for the first time that under the Obama administration the communication records of millions of U.S. citizens were being collected indiscriminately and in bulk, regardless of whether they were suspected of any wrongdoing.

The Associated Press could not authenticate the order because documents from the court are classified.

Sen. Ron Wyden, D-Ore., said the Obama administration should disclose the facts.

"I think that they have an obligation to respond immediately," said Wyden, a frequent critic of government violations of privacy.

“I read intelligence carefully, and I know that people are trying to get to us. This is the reason why we keep TSA doing what it’s doing. This is the reason why the FBI now has 10,000 people doing intelligence on counterterrorism,” said Senate Intelligence Chairwoman Dianne Feinstein, D-Calif.

The administration official spoke on condition of anonymity because the official was not authorized to publicly discuss classified matters.

Verizon spokesman Ed McFadden said Wednesday the company had no comment. The NSA had no immediate comment.

Verizon Communications Inc. listed 121 million customers in its first-quarter earnings report this April — 98.9 million wireless customers, 11.7 million residential phone lines and about 10 million commercial lines. The court order didn't specify which type of phone customers' records were being tracked.

Under the terms of the order, the phone numbers of both parties on a call are handed over, as are location data, call duration, unique identifiers, and the time and duration of all calls. The contents of the conversation itself are not covered, The Guardian said.

The administration official said, "On its face, the order reprinted in the article does not allow the government to listen in on anyone's telephone calls."

The broad, unlimited nature of the records being handed over to the NSA is unusual. FISA court orders typically direct the production of records pertaining to a specific named target suspected of being an agent of a terrorist group or foreign state, or a finite set of individually named targets. NSA warrantless wiretapping during the George W. Bush administration after the 9/11 attacks was very controversial.

The FISA court order, signed by Judge Roger Vinson, compelled Verizon to provide the NSA with electronic copies of "all call detail records or telephony metadata created by Verizon for communications between the United States and abroad" or "wholly within the United States, including local telephone calls," The Guardian said.

The law on which the order explicitly relies is the "business records" provision of the USA Patriot Act.